Medication for Early Appendicitis
For early uncomplicated appendicitis, administer a single preoperative dose of broad-spectrum antibiotics (cefoxitin, ertapenem, moxifloxacin, or ticarcillin-clavulanate as monotherapy, OR metronidazole combined with cefazolin/cefuroxime/ceftriaxone/levofloxacin/ciprofloxacin) within 0-60 minutes before surgical incision, with NO postoperative antibiotics needed if adequate source control is achieved. 1
Preoperative Antibiotic Prophylaxis
Single-dose regimen for uncomplicated appendicitis:
- A single preoperative dose of broad-spectrum antibiotics given 0-60 minutes before surgical skin incision effectively decreases wound infection and postoperative intra-abdominal abscess formation, regardless of the degree of appendiceal inflammation 1
- No postoperative antibiotics are recommended for uncomplicated appendicitis 1
Specific Antibiotic Regimens
For mild-to-moderate community-acquired appendicitis, preferred single-agent options include: 1
- Ticarcillin-clavulanate
- Cefoxitin
- Ertapenem 2
- Moxifloxacin
- Tigecycline (though concerns exist about overly broad spectrum) 1
Combination regimens (metronidazole PLUS one of the following): 1
- Cefazolin
- Cefuroxime
- Ceftriaxone
- Cefotaxime
- Levofloxacin
- Ciprofloxacin
Antibiotics to AVOID: 1
- Ampicillin-sulbactam (high E. coli resistance rates)
- Cefotetan (increasing Bacteroides fragilis resistance)
- Clindamycin (increasing B. fragilis resistance)
- Aminoglycosides for routine use (toxicity concerns)
Non-Operative Antibiotic Management
For patients managed non-operatively with antibiotics alone:
- Intravenous piperacillin-tazobactam followed by oral ciprofloxacin plus metronidazole for total 7-10 days is effective in approximately 70-77% of uncomplicated cases 3, 4
- Alternative: Amoxicillin-clavulanate (250/25 mg/kg IV 4 times daily, maximum 6,000/600 mg/day) plus gentamicin (7 mg/kg once daily) for 48-72 hours, then oral continuation for total 7 days 5
- Oral metronidazole alone (500 mg every 8 hours for adults) can be effective and cost-efficient 6
- Success rates at 1 year: 63-73% remain asymptomatic without surgery 3, 7
- Recurrence rates: 23-27% require subsequent appendectomy within 1 year 3, 7, 4
High-Risk Features Predicting Antibiotic Failure
CT findings associated with ~40% antibiotic treatment failure (surgery recommended): 3
- Appendicolith present
- Mass effect
- Appendiceal diameter >13 mm
Patients WITHOUT these high-risk features can be offered either appendectomy or antibiotics as first-line therapy 3
Complicated Appendicitis (Perforation/Abscess)
For complicated appendicitis with adequate source control:
- Postoperative antibiotics should NOT exceed 3-5 days 1
- Broader-spectrum coverage required: piperacillin-tazobactam, ampicillin-sulbactam, ticarcillin-clavulanate, or imipenem-cilastatin 1
- Most common combination for perforated appendicitis: ampicillin + clindamycin (or metronidazole) + gentamicin 1
- Alternatives: ceftriaxone-metronidazole or ticarcillin-clavulanate plus gentamicin 1
Pediatric Considerations
Children with non-perforated appendicitis:
- Single broad-spectrum antibiotic (second- or third-generation cephalosporin like cefoxitin or cefotetan) 1
- No postoperative antibiotics recommended 1
Children with complicated appendicitis:
- Early switch to oral antibiotics after 48 hours is safe and effective 1
- Total antibiotic duration should be <7 days postoperatively 1
- Extended-spectrum antibiotics offer no advantage over narrower-spectrum agents 1
Critical Pitfalls to Avoid
- Do not routinely cover Enterococcus in community-acquired appendicitis 1
- Do not provide empiric antifungal coverage for Candida 1
- Avoid quinolones unless local E. coli susceptibility is ≥90% 1
- Avoid moxifloxacin if patient received quinolones within 3 months (likely quinolone-resistant B. fragilis) 1
- Do not prolong antibiotics beyond 3-5 days postoperatively in complicated cases with adequate source control 1